[mirror_ubuntu-zesty-kernel.git] / drivers / mtd / mtd_blkdevs.c

/*
 * (C) 2003 David Woodhouse <dwmw2@infradead.org>
 *
 * Interface to Linux 2.5 block layer for MTD 'translation layers'.
 *
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/fs.h>
#include <linux/mtd/blktrans.h>
#include <linux/mtd/mtd.h>
#include <linux/blkdev.h>
#include <linux/blkpg.h>
#include <linux/freezer.h>
#include <linux/spinlock.h>
#include <linux/hdreg.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/kthread.h>
#include <asm/uaccess.h>

#include "mtdcore.h"

static LIST_HEAD(blktrans_majors);

struct mtd_blkcore_priv {
	struct task_struct *thread;
	struct request_queue *rq;
	spinlock_t queue_lock;
};

static int blktrans_discard_request(struct request_queue *q,
				    struct request *req)
{
	req->cmd_type = REQ_TYPE_LINUX_BLOCK;
	req->cmd[0] = REQ_LB_OP_DISCARD;
	return 0;
}

static int do_blktrans_request(struct mtd_blktrans_ops *tr,
			       struct mtd_blktrans_dev *dev,
			       struct request *req)
{
	unsigned long block, nsect;
	char *buf;

	block = req->sector << 9 >> tr->blkshift;
	nsect = req->current_nr_sectors << 9 >> tr->blkshift;

	buf = req->buffer;

	if (req->cmd_type == REQ_TYPE_LINUX_BLOCK &&
	    req->cmd[0] == REQ_LB_OP_DISCARD)
		return !tr->discard(dev, block, nsect);

	if (!blk_fs_request(req))
		return 0;

	if (req->sector + req->current_nr_sectors > get_capacity(req->rq_disk))
		return 0;

	switch(rq_data_dir(req)) {
	case READ:
		for (; nsect > 0; nsect--, block++, buf += tr->blksize)
			if (tr->readsect(dev, block, buf))
				return 0;
		return 1;

	case WRITE:
		if (!tr->writesect)
			return 0;

		for (; nsect > 0; nsect--, block++, buf += tr->blksize)
			if (tr->writesect(dev, block, buf))
				return 0;
		return 1;

	default:
		printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
		return 0;
	}
}

static int mtd_blktrans_thread(void *arg)
{
	struct mtd_blktrans_ops *tr = arg;
	struct request_queue *rq = tr->blkcore_priv->rq;

	/* we might get involved when memory gets low, so use PF_MEMALLOC */
	current->flags |= PF_MEMALLOC;

	spin_lock_irq(rq->queue_lock);
	while (!kthread_should_stop()) {
		struct request *req;
		struct mtd_blktrans_dev *dev;
		int res = 0;

		req = elv_next_request(rq);

		if (!req) {
			set_current_state(TASK_INTERRUPTIBLE);
			spin_unlock_irq(rq->queue_lock);
			schedule();
			spin_lock_irq(rq->queue_lock);
			continue;
		}

		dev = req->rq_disk->private_data;
		tr = dev->tr;

		spin_unlock_irq(rq->queue_lock);

		mutex_lock(&dev->lock);
		res = do_blktrans_request(tr, dev, req);
		mutex_unlock(&dev->lock);

		spin_lock_irq(rq->queue_lock);

		end_request(req, res);
	}
	spin_unlock_irq(rq->queue_lock);

	return 0;
}

static void mtd_blktrans_request(struct request_queue *rq)
{
	struct mtd_blktrans_ops *tr = rq->queuedata;
	wake_up_process(tr->blkcore_priv->thread);
}


static int blktrans_open(struct inode *i, struct file *f)
{
	struct mtd_blktrans_dev *dev;
	struct mtd_blktrans_ops *tr;
	int ret = -ENODEV;

	dev = i->i_bdev->bd_disk->private_data;
	tr = dev->tr;

	if (!try_module_get(dev->mtd->owner))
		goto out;

	if (!try_module_get(tr->owner))
		goto out_tr;

	/* FIXME: Locking. A hot pluggable device can go away
	   (del_mtd_device can be called for it) without its module
	   being unloaded. */
	dev->mtd->usecount++;

	ret = 0;
	if (tr->open && (ret = tr->open(dev))) {
		dev->mtd->usecount--;
		module_put(dev->mtd->owner);
	out_tr:
		module_put(tr->owner);
	}
 out:
	return ret;
}

static int blktrans_release(struct inode *i, struct file *f)
{
	struct mtd_blktrans_dev *dev;
	struct mtd_blktrans_ops *tr;
	int ret = 0;

	dev = i->i_bdev->bd_disk->private_data;
	tr = dev->tr;

	if (tr->release)
		ret = tr->release(dev);

	if (!ret) {
		dev->mtd->usecount--;
		module_put(dev->mtd->owner);
		module_put(tr->owner);
	}

	return ret;
}

static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;

	if (dev->tr->getgeo)
		return dev->tr->getgeo(dev, geo);
	return -ENOTTY;
}

static int blktrans_ioctl(struct inode *inode, struct file *file,
			      unsigned int cmd, unsigned long arg)
{
	struct mtd_blktrans_dev *dev = inode->i_bdev->bd_disk->private_data;
	struct mtd_blktrans_ops *tr = dev->tr;

	switch (cmd) {
	case BLKFLSBUF:
		if (tr->flush)
			return tr->flush(dev);
		/* The core code did the work, we had nothing to do. */
		return 0;
	default:
		return -ENOTTY;
	}
}

static struct block_device_operations mtd_blktrans_ops = {
	.owner		= THIS_MODULE,
	.__open		= blktrans_open,
	.__release	= blktrans_release,
	.__ioctl		= blktrans_ioctl,
	.getgeo		= blktrans_getgeo,
};

int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
{
	struct mtd_blktrans_ops *tr = new->tr;
	struct mtd_blktrans_dev *d;
	int last_devnum = -1;
	struct gendisk *gd;

	if (mutex_trylock(&mtd_table_mutex)) {
		mutex_unlock(&mtd_table_mutex);
		BUG();
	}

	list_for_each_entry(d, &tr->devs, list) {
		if (new->devnum == -1) {
			/* Use first free number */
			if (d->devnum != last_devnum+1) {
				/* Found a free devnum. Plug it in here */
				new->devnum = last_devnum+1;
				list_add_tail(&new->list, &d->list);
				goto added;
			}
		} else if (d->devnum == new->devnum) {
			/* Required number taken */
			return -EBUSY;
		} else if (d->devnum > new->devnum) {
			/* Required number was free */
			list_add_tail(&new->list, &d->list);
			goto added;
		}
		last_devnum = d->devnum;
	}
	if (new->devnum == -1)
		new->devnum = last_devnum+1;

	if ((new->devnum << tr->part_bits) > 256) {
		return -EBUSY;
	}

	list_add_tail(&new->list, &tr->devs);
 added:
	mutex_init(&new->lock);
	if (!tr->writesect)
		new->readonly = 1;

	gd = alloc_disk(1 << tr->part_bits);
	if (!gd) {
		list_del(&new->list);
		return -ENOMEM;
	}
	gd->major = tr->major;
	gd->first_minor = (new->devnum) << tr->part_bits;
	gd->fops = &mtd_blktrans_ops;

	if (tr->part_bits)
		if (new->devnum < 26)
			snprintf(gd->disk_name, sizeof(gd->disk_name),
				 "%s%c", tr->name, 'a' + new->devnum);
		else
			snprintf(gd->disk_name, sizeof(gd->disk_name),
				 "%s%c%c", tr->name,
				 'a' - 1 + new->devnum / 26,
				 'a' + new->devnum % 26);
	else
		snprintf(gd->disk_name, sizeof(gd->disk_name),
			 "%s%d", tr->name, new->devnum);

	/* 2.5 has capacity in units of 512 bytes while still
	   having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
	set_capacity(gd, (new->size * tr->blksize) >> 9);

	gd->private_data = new;
	new->blkcore_priv = gd;
	gd->queue = tr->blkcore_priv->rq;

	if (new->readonly)
		set_disk_ro(gd, 1);

	add_disk(gd);

	return 0;
}

int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
{
	if (mutex_trylock(&mtd_table_mutex)) {
		mutex_unlock(&mtd_table_mutex);
		BUG();
	}

	list_del(&old->list);

	del_gendisk(old->blkcore_priv);
	put_disk(old->blkcore_priv);

	return 0;
}

static void blktrans_notify_remove(struct mtd_info *mtd)
{
	struct mtd_blktrans_ops *tr;
	struct mtd_blktrans_dev *dev, *next;

	list_for_each_entry(tr, &blktrans_majors, list)
		list_for_each_entry_safe(dev, next, &tr->devs, list)
			if (dev->mtd == mtd)
				tr->remove_dev(dev);
}

static void blktrans_notify_add(struct mtd_info *mtd)
{
	struct mtd_blktrans_ops *tr;

	if (mtd->type == MTD_ABSENT)
		return;

	list_for_each_entry(tr, &blktrans_majors, list)
		tr->add_mtd(tr, mtd);
}

static struct mtd_notifier blktrans_notifier = {
	.add = blktrans_notify_add,
	.remove = blktrans_notify_remove,
};

int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
{
	int ret, i;

	/* Register the notifier if/when the first device type is
	   registered, to prevent the link/init ordering from fucking
	   us over. */
	if (!blktrans_notifier.list.next)
		register_mtd_user(&blktrans_notifier);

	tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
	if (!tr->blkcore_priv)
		return -ENOMEM;

	mutex_lock(&mtd_table_mutex);

	ret = register_blkdev(tr->major, tr->name);
	if (ret) {
		printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
		       tr->name, tr->major, ret);
		kfree(tr->blkcore_priv);
		mutex_unlock(&mtd_table_mutex);
		return ret;
	}
	spin_lock_init(&tr->blkcore_priv->queue_lock);

	tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
	if (!tr->blkcore_priv->rq) {
		unregister_blkdev(tr->major, tr->name);
		kfree(tr->blkcore_priv);
		mutex_unlock(&mtd_table_mutex);
		return -ENOMEM;
	}

	tr->blkcore_priv->rq->queuedata = tr;
	blk_queue_hardsect_size(tr->blkcore_priv->rq, tr->blksize);
	if (tr->discard)
		blk_queue_set_discard(tr->blkcore_priv->rq,
				      blktrans_discard_request);

	tr->blkshift = ffs(tr->blksize) - 1;

	tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
			"%sd", tr->name);
	if (IS_ERR(tr->blkcore_priv->thread)) {
		blk_cleanup_queue(tr->blkcore_priv->rq);
		unregister_blkdev(tr->major, tr->name);
		kfree(tr->blkcore_priv);
		mutex_unlock(&mtd_table_mutex);
		return PTR_ERR(tr->blkcore_priv->thread);
	}

	INIT_LIST_HEAD(&tr->devs);
	list_add(&tr->list, &blktrans_majors);

	for (i=0; i<MAX_MTD_DEVICES; i++) {
		if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
			tr->add_mtd(tr, mtd_table[i]);
	}

	mutex_unlock(&mtd_table_mutex);

	return 0;
}

int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
{
	struct mtd_blktrans_dev *dev, *next;

	mutex_lock(&mtd_table_mutex);

	/* Clean up the kernel thread */
	kthread_stop(tr->blkcore_priv->thread);

	/* Remove it from the list of active majors */
	list_del(&tr->list);

	list_for_each_entry_safe(dev, next, &tr->devs, list)
		tr->remove_dev(dev);

	blk_cleanup_queue(tr->blkcore_priv->rq);
	unregister_blkdev(tr->major, tr->name);

	mutex_unlock(&mtd_table_mutex);

	kfree(tr->blkcore_priv);

	BUG_ON(!list_empty(&tr->devs));
	return 0;
}

static void __exit mtd_blktrans_exit(void)
{
	/* No race here -- if someone's currently in register_mtd_blktrans
	   we're screwed anyway. */
	if (blktrans_notifier.list.next)
		unregister_mtd_user(&blktrans_notifier);
}

module_exit(mtd_blktrans_exit);

EXPORT_SYMBOL_GPL(register_mtd_blktrans);
EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);

MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	2	* (C) 2003 David Woodhouse <dwmw2@infradead.org>
	3	*
	4	* Interface to Linux 2.5 block layer for MTD 'translation layers'.
	5	*
	6	*/
	7
	8	#include <linux/kernel.h>
	9	#include <linux/slab.h>
	10	#include <linux/module.h>
	11	#include <linux/list.h>
	12	#include <linux/fs.h>
	13	#include <linux/mtd/blktrans.h>
	14	#include <linux/mtd/mtd.h>
	15	#include <linux/blkdev.h>
	16	#include <linux/blkpg.h>
83144186	17	#include <linux/freezer.h>
1da177e4 LT	18	#include <linux/spinlock.h>
	19	#include <linux/hdreg.h>
	20	#include <linux/init.h>
48b19268	21	#include <linux/mutex.h>
99f9b243	22	#include <linux/kthread.h>
1da177e4	23	#include <asm/uaccess.h>
1da177e4	24
356d70f1	25	#include "mtdcore.h"
1da177e4	26
356d70f1	27	static LIST_HEAD(blktrans_majors);
1da177e4 LT	28
1da177e4 LT	29	struct mtd_blkcore_priv {
3e67fe45	30	struct task_struct *thread;
1da177e4 LT	31	struct request_queue *rq;
	32	spinlock_t queue_lock;
	33	};
	34
eae9acd1 DW	35	static int blktrans_discard_request(struct request_queue *q,
	36	struct request *req)
	37	{
	38	req->cmd_type = REQ_TYPE_LINUX_BLOCK;
	39	req->cmd[0] = REQ_LB_OP_DISCARD;
	40	return 0;
	41	}
	42
1da177e4 LT	43	static int do_blktrans_request(struct mtd_blktrans_ops *tr,
	44	struct mtd_blktrans_dev *dev,
	45	struct request *req)
	46	{
	47	unsigned long block, nsect;
	48	char *buf;
	49
19187672 RP	50	block = req->sector << 9 >> tr->blkshift;
	51	nsect = req->current_nr_sectors << 9 >> tr->blkshift;
	52
1da177e4 LT	53	buf = req->buffer;
1da177e4 LT	54
eae9acd1 DW	55	if (req->cmd_type == REQ_TYPE_LINUX_BLOCK &&
	56	req->cmd[0] == REQ_LB_OP_DISCARD)
	57	return !tr->discard(dev, block, nsect);
	58
4aff5e23	59	if (!blk_fs_request(req))
1da177e4 LT	60	return 0;
1da177e4 LT	61
19187672	62	if (req->sector + req->current_nr_sectors > get_capacity(req->rq_disk))
1da177e4 LT	63	return 0;
	64
	65	switch(rq_data_dir(req)) {
	66	case READ:
19187672	67	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4 LT	68	if (tr->readsect(dev, block, buf))
	69	return 0;
	70	return 1;
	71
	72	case WRITE:
	73	if (!tr->writesect)
	74	return 0;
	75
19187672	76	for (; nsect > 0; nsect--, block++, buf += tr->blksize)
1da177e4 LT	77	if (tr->writesect(dev, block, buf))
	78	return 0;
	79	return 1;
	80
	81	default:
9a292308	82	printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
1da177e4 LT	83	return 0;
	84	}
	85	}
	86
	87	static int mtd_blktrans_thread(void *arg)
	88	{
	89	struct mtd_blktrans_ops *tr = arg;
	90	struct request_queue *rq = tr->blkcore_priv->rq;
	91
	92	/* we might get involved when memory gets low, so use PF_MEMALLOC */
83144186	93	current->flags \|= PF_MEMALLOC;
1da177e4	94
1da177e4	95	spin_lock_irq(rq->queue_lock);
3e67fe45	96	while (!kthread_should_stop()) {
1da177e4 LT	97	struct request *req;
	98	struct mtd_blktrans_dev *dev;
	99	int res = 0;
1da177e4 LT	100
	101	req = elv_next_request(rq);
	102
	103	if (!req) {
1da177e4	104	set_current_state(TASK_INTERRUPTIBLE);
1da177e4	105	spin_unlock_irq(rq->queue_lock);
1da177e4	106	schedule();
1da177e4	107	spin_lock_irq(rq->queue_lock);
1da177e4 LT	108	continue;
	109	}
	110
	111	dev = req->rq_disk->private_data;
	112	tr = dev->tr;
	113
	114	spin_unlock_irq(rq->queue_lock);
	115
48b19268	116	mutex_lock(&dev->lock);
1da177e4	117	res = do_blktrans_request(tr, dev, req);
48b19268	118	mutex_unlock(&dev->lock);
1da177e4 LT	119
	120	spin_lock_irq(rq->queue_lock);
	121
	122	end_request(req, res);
	123	}
	124	spin_unlock_irq(rq->queue_lock);
	125
3e67fe45	126	return 0;
1da177e4 LT	127	}
	128
	129	static void mtd_blktrans_request(struct request_queue *rq)
	130	{
	131	struct mtd_blktrans_ops *tr = rq->queuedata;
3e67fe45	132	wake_up_process(tr->blkcore_priv->thread);
1da177e4 LT	133	}
	134
	135
	136	static int blktrans_open(struct inode i, struct file f)
	137	{
	138	struct mtd_blktrans_dev *dev;
	139	struct mtd_blktrans_ops *tr;
	140	int ret = -ENODEV;
	141
	142	dev = i->i_bdev->bd_disk->private_data;
	143	tr = dev->tr;
	144
	145	if (!try_module_get(dev->mtd->owner))
	146	goto out;
	147
	148	if (!try_module_get(tr->owner))
	149	goto out_tr;
	150
97894cda	151	/* FIXME: Locking. A hot pluggable device can go away
1da177e4 LT	152	(del_mtd_device can be called for it) without its module
	153	being unloaded. */
	154	dev->mtd->usecount++;
	155
	156	ret = 0;
	157	if (tr->open && (ret = tr->open(dev))) {
	158	dev->mtd->usecount--;
	159	module_put(dev->mtd->owner);
	160	out_tr:
	161	module_put(tr->owner);
	162	}
	163	out:
	164	return ret;
	165	}
	166
	167	static int blktrans_release(struct inode i, struct file f)
	168	{
	169	struct mtd_blktrans_dev *dev;
	170	struct mtd_blktrans_ops *tr;
	171	int ret = 0;
	172
	173	dev = i->i_bdev->bd_disk->private_data;
	174	tr = dev->tr;
	175
	176	if (tr->release)
	177	ret = tr->release(dev);
	178
	179	if (!ret) {
	180	dev->mtd->usecount--;
	181	module_put(dev->mtd->owner);
	182	module_put(tr->owner);
	183	}
	184
	185	return ret;
	186	}
	187
a885c8c4 CH	188	static int blktrans_getgeo(struct block_device bdev, struct hd_geometry geo)
	189	{
	190	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
	191
	192	if (dev->tr->getgeo)
	193	return dev->tr->getgeo(dev, geo);
	194	return -ENOTTY;
	195	}
1da177e4	196
97894cda	197	static int blktrans_ioctl(struct inode inode, struct file file,
1da177e4 LT	198	unsigned int cmd, unsigned long arg)
	199	{
	200	struct mtd_blktrans_dev *dev = inode->i_bdev->bd_disk->private_data;
	201	struct mtd_blktrans_ops *tr = dev->tr;
	202
	203	switch (cmd) {
	204	case BLKFLSBUF:
	205	if (tr->flush)
	206	return tr->flush(dev);
	207	/* The core code did the work, we had nothing to do. */
	208	return 0;
1da177e4 LT	209	default:
	210	return -ENOTTY;
	211	}
	212	}
	213
8f026f75	214	static struct block_device_operations mtd_blktrans_ops = {
1da177e4	215	.owner = THIS_MODULE,
d4430d62 AV	216	.__open = blktrans_open,
	217	.__release = blktrans_release,
	218	.__ioctl = blktrans_ioctl,
a885c8c4	219	.getgeo = blktrans_getgeo,
1da177e4 LT	220	};
	221
	222	int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
	223	{
	224	struct mtd_blktrans_ops *tr = new->tr;
71a928c0	225	struct mtd_blktrans_dev *d;
1da177e4 LT	226	int last_devnum = -1;
	227	struct gendisk *gd;
	228
b3561ea9	229	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	230	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	231	BUG();
	232	}
	233
71a928c0	234	list_for_each_entry(d, &tr->devs, list) {
1da177e4 LT	235	if (new->devnum == -1) {
	236	/* Use first free number */
	237	if (d->devnum != last_devnum+1) {
	238	/* Found a free devnum. Plug it in here */
	239	new->devnum = last_devnum+1;
	240	list_add_tail(&new->list, &d->list);
	241	goto added;
	242	}
	243	} else if (d->devnum == new->devnum) {
	244	/* Required number taken */
	245	return -EBUSY;
	246	} else if (d->devnum > new->devnum) {
	247	/* Required number was free */
	248	list_add_tail(&new->list, &d->list);
	249	goto added;
97894cda	250	}
1da177e4 LT	251	last_devnum = d->devnum;
	252	}
	253	if (new->devnum == -1)
	254	new->devnum = last_devnum+1;
	255
	256	if ((new->devnum << tr->part_bits) > 256) {
	257	return -EBUSY;
	258	}
	259
1da177e4 LT	260	list_add_tail(&new->list, &tr->devs);
1da177e4 LT	261	added:
ce37ab42	262	mutex_init(&new->lock);
1da177e4 LT	263	if (!tr->writesect)
	264	new->readonly = 1;
	265
	266	gd = alloc_disk(1 << tr->part_bits);
	267	if (!gd) {
	268	list_del(&new->list);
	269	return -ENOMEM;
	270	}
	271	gd->major = tr->major;
	272	gd->first_minor = (new->devnum) << tr->part_bits;
	273	gd->fops = &mtd_blktrans_ops;
97894cda	274
65a8de36 TP	275	if (tr->part_bits)
	276	if (new->devnum < 26)
	277	snprintf(gd->disk_name, sizeof(gd->disk_name),
	278	"%s%c", tr->name, 'a' + new->devnum);
	279	else
	280	snprintf(gd->disk_name, sizeof(gd->disk_name),
	281	"%s%c%c", tr->name,
	282	'a' - 1 + new->devnum / 26,
	283	'a' + new->devnum % 26);
	284	else
	285	snprintf(gd->disk_name, sizeof(gd->disk_name),
	286	"%s%d", tr->name, new->devnum);
1da177e4 LT	287
	288	/* 2.5 has capacity in units of 512 bytes while still
	289	having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
19187672	290	set_capacity(gd, (new->size * tr->blksize) >> 9);
1da177e4 LT	291
	292	gd->private_data = new;
	293	new->blkcore_priv = gd;
	294	gd->queue = tr->blkcore_priv->rq;
	295
	296	if (new->readonly)
	297	set_disk_ro(gd, 1);
	298
	299	add_disk(gd);
97894cda	300
1da177e4 LT	301	return 0;
	302	}
	303
	304	int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
	305	{
b3561ea9	306	if (mutex_trylock(&mtd_table_mutex)) {
48b19268	307	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	308	BUG();
	309	}
	310
	311	list_del(&old->list);
	312
	313	del_gendisk(old->blkcore_priv);
	314	put_disk(old->blkcore_priv);
97894cda	315
1da177e4 LT	316	return 0;
	317	}
	318
	319	static void blktrans_notify_remove(struct mtd_info *mtd)
	320	{
71a928c0 CM	321	struct mtd_blktrans_ops *tr;
71a928c0 CM	322	struct mtd_blktrans_dev dev, next;
1da177e4	323
71a928c0 CM	324	list_for_each_entry(tr, &blktrans_majors, list)
71a928c0 CM	325	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4 LT	326	if (dev->mtd == mtd)
1da177e4 LT	327	tr->remove_dev(dev);
1da177e4 LT	328	}
	329
	330	static void blktrans_notify_add(struct mtd_info *mtd)
	331	{
71a928c0	332	struct mtd_blktrans_ops *tr;
1da177e4 LT	333
	334	if (mtd->type == MTD_ABSENT)
	335	return;
	336
71a928c0	337	list_for_each_entry(tr, &blktrans_majors, list)
1da177e4	338	tr->add_mtd(tr, mtd);
1da177e4 LT	339	}
	340
	341	static struct mtd_notifier blktrans_notifier = {
	342	.add = blktrans_notify_add,
	343	.remove = blktrans_notify_remove,
	344	};
97894cda	345
1da177e4 LT	346	int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
	347	{
	348	int ret, i;
	349
97894cda	350	/* Register the notifier if/when the first device type is
1da177e4 LT	351	registered, to prevent the link/init ordering from fucking
	352	us over. */
	353	if (!blktrans_notifier.list.next)
	354	register_mtd_user(&blktrans_notifier);
	355
95b93a0c	356	tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
1da177e4 LT	357	if (!tr->blkcore_priv)
	358	return -ENOMEM;
	359
48b19268	360	mutex_lock(&mtd_table_mutex);
1da177e4 LT	361
	362	ret = register_blkdev(tr->major, tr->name);
	363	if (ret) {
	364	printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
	365	tr->name, tr->major, ret);
	366	kfree(tr->blkcore_priv);
48b19268	367	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	368	return ret;
	369	}
	370	spin_lock_init(&tr->blkcore_priv->queue_lock);
1da177e4 LT	371
	372	tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
	373	if (!tr->blkcore_priv->rq) {
	374	unregister_blkdev(tr->major, tr->name);
	375	kfree(tr->blkcore_priv);
48b19268	376	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	377	return -ENOMEM;
	378	}
	379
	380	tr->blkcore_priv->rq->queuedata = tr;
19187672	381	blk_queue_hardsect_size(tr->blkcore_priv->rq, tr->blksize);
eae9acd1 DW	382	if (tr->discard)
	383	blk_queue_set_discard(tr->blkcore_priv->rq,
	384	blktrans_discard_request);
	385
19187672	386	tr->blkshift = ffs(tr->blksize) - 1;
1da177e4	387
3e67fe45 CH	388	tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
	389	"%sd", tr->name);
	390	if (IS_ERR(tr->blkcore_priv->thread)) {
1da177e4 LT	391	blk_cleanup_queue(tr->blkcore_priv->rq);
	392	unregister_blkdev(tr->major, tr->name);
	393	kfree(tr->blkcore_priv);
48b19268	394	mutex_unlock(&mtd_table_mutex);
3e67fe45	395	return PTR_ERR(tr->blkcore_priv->thread);
97894cda	396	}
1da177e4	397
1da177e4 LT	398	INIT_LIST_HEAD(&tr->devs);
	399	list_add(&tr->list, &blktrans_majors);
	400
	401	for (i=0; i<MAX_MTD_DEVICES; i++) {
	402	if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
	403	tr->add_mtd(tr, mtd_table[i]);
	404	}
	405
48b19268	406	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	407
	408	return 0;
	409	}
	410
	411	int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
	412	{
71a928c0	413	struct mtd_blktrans_dev dev, next;
1da177e4	414
48b19268	415	mutex_lock(&mtd_table_mutex);
1da177e4 LT	416
1da177e4 LT	417	/* Clean up the kernel thread */
3e67fe45	418	kthread_stop(tr->blkcore_priv->thread);
1da177e4 LT	419
	420	/* Remove it from the list of active majors */
	421	list_del(&tr->list);
	422
71a928c0	423	list_for_each_entry_safe(dev, next, &tr->devs, list)
1da177e4	424	tr->remove_dev(dev);
1da177e4	425
1da177e4 LT	426	blk_cleanup_queue(tr->blkcore_priv->rq);
	427	unregister_blkdev(tr->major, tr->name);
	428
48b19268	429	mutex_unlock(&mtd_table_mutex);
1da177e4 LT	430
	431	kfree(tr->blkcore_priv);
	432
373ebfbf	433	BUG_ON(!list_empty(&tr->devs));
1da177e4 LT	434	return 0;
	435	}
	436
	437	static void __exit mtd_blktrans_exit(void)
	438	{
	439	/* No race here -- if someone's currently in register_mtd_blktrans
	440	we're screwed anyway. */
	441	if (blktrans_notifier.list.next)
	442	unregister_mtd_user(&blktrans_notifier);
	443	}
	444
	445	module_exit(mtd_blktrans_exit);
	446
	447	EXPORT_SYMBOL_GPL(register_mtd_blktrans);
	448	EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
	449	EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
	450	EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
	451
	452	MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
	453	MODULE_LICENSE("GPL");
	454	MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");